Efficient Structures for Off-Highway Applications

TWI has been working with JCB, backed by Tata Steel, in an Innovate UK supported initiative, to develop new designs, and their associated manufacturing methods, for lighter weight, next-generation off-highway vehicles.

Project background

A move away from the heavier designs traditionally associated with off-highway vehicles is seeing their operating efficiency improve, their productivity on a given job increase, and their impact on the environment reduce.

In the ELSOHA project, Tata Steel has been assisting JCB in the modelling and optimisation of key vehicle part designs to help achieve these goals. Nevertheless, the fact remains that efficient volume-manufacturing methods then have to be found for making these new designs, in a competitive, cost-conscious environment, to turn them in to a commercial reality. This is where TWI has stepped in, with its know-how on the joining, and joint properties, of a range of possible metal and even non-metal candidates for these future designs, set against a backdrop of where these materials, and joining processes, are already used in other industries.

Work programme

With arc welding being the production joining process already well known and understood by JCB, in this project, laser welding, hybrid laser-arc welding, rotary friction welding and adhesive bonding were selected early on as the alternative, relevant processes of most interest. (A separate case study highlighting some of the work carried out on adhesively bonded joints can be seen here - 'ELSOHA - Efficient Lightweight Structures in Off-Highway Applications').

The project team went on to identify that two key structural elements already familiar to the automotive and shipbuilding industries, could be of most benefit to JCB to strip out weight without compromising performance: namely sandwich panels and tailored blanks.

With these decisions taken, TWI then developed, through welding trials, suitable processes, parameters and fixtures for the laser stake welding and hybrid laser-arc butt welding of demonstrator panels and tailored sections.

These demonstrations also took full advantage of the novel, higher performance steels on offer from Tata.

Coupon-level property testing has already indicated that both of these laser-based welding processes can, if used correctly, result in joints in these steels with considerable strength.

This work has helped JCB assemble a suite of design-materials-joining process combinations, which may enable the manufacture of novel, lighter-weight structures going forwards in to the future.